A communication failure caused by a software bag or an error in operation might stop a controlling part in a base transceiver station for connecting with a mobile station (for example, mobile terminal, portable terminal) without an alarm generation in a 3GPP (third generation partnership project) system using W-CDMA (wideband code division multiple access), UMTS (universal mobile telecommunication system), or the like or a mobile communication system using WiMAX (worldwide interoperability for microwave access) or the like.
If a base transceiver station is placed in such a state, the base transceiver station makes no response to a connection request from a mobile station and falls into a situation where communications may not be performed. Such a state, that is, a state in which a base transceiver station makes no response to a mobile station will be referred to as a “silent state.”
As a method for detecting such a “silent state” of a base transceiver station, Japanese Laid-open Patent Publication No. 10-13323 discloses that a test mobile station is provided at each base transceiver station, the mobile station is connected to a maintenance network of the base transceiver stations so that control for a call can be performed remotely, and when a user complaint is received or when a periodical test is performed, control for a call is performed on a test mobile station so as to check whether the base transceiver station in question can be connected.
However, in this case, a special test terminal is provided at each base transceiver station, so the costs of base transceiver stations or the installation cost are increased.
Also, it is conceivable to determine whether a base transceiver station is placed in a “silent state” by checking a user traffic based on such as statistic data collected from base transceiver stations. However, in this case, it is necessary to compare whether there is actually no user traffic or whether there appears to be no user traffic due to an abnormality of a base transceiver station, with normal traffic situation or the like.
For this reason, the past data is also referred to for analysis. Therefore, time is required until a “silent state” of a base transceiver station is detected.